1. Field of the Invention
The invention lies in the field of washing appliances. The invention relates to a drive apparatus for a washing machine having a laundry drum that is mounted within a bearing sleeve of a stiff supporting star and is fitted to a bottom wall of a lye or suds container through an at least approximately horizontal shaft. As such, the drive device can be mounted on the rear face of the suds container and includes a flat motor with a stator supporting part and field windings and with a rotor and magnetic poles and drives the laundry drum directly.
Such a drive apparatus is disclosed in German Published, Non-Prosecuted Patent Application DE 197 26 246 A1, corresponding to U.S. Pat. No. 6,131,422 to Skrippek et al. In the Skrippek drive apparatus, the stator supporting part and the rotor of the motor are detachably connected to one another for the duration of the transportation process until they are finally mounted on a supporting part, which is mounted on the bottom wall of the suds container, with the relative position of the stator supporting part with respect to the rotor corresponding to the operating position. The configuration ensures the necessary compliance with the internal tolerances required for correct operation of the motor (mainly the positioning of the field windings with respect to the magnetic rotor poles).
It is accordingly an object of the invention to provide a drive apparatus for a washing machine that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that supplies the motor to the washing machine manufacturer""s factory completely preassembled and tested without any need, during installation of the motor on the washing machine, to take any action that could endanger compliance with the tolerances required for correct operation of the motor. The invention also simplifies the assembly process in the washing machine factory.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a drive apparatus for a washing machine having a laundry drum and a suds container with a rear wall, including a stiff supporting star having a bearing sleeve for mounting the laundry drum of the washing machine in the bearing sleeve, a substantially horizontal shaft for connecting the supporting star to the rear wall of the suds container, the shaft having a bearing, a flat motor for directly driving the laundry drum, the motor to be mounted on the rear wall of the suds container, the motor connected to the supporting star and having a stator support, field windings connected to the stator support, a rotor connected to the shaft through the bearing, and magnetic poles connected to the rotor, and a further bearing connecting the stator support to the rotor.
The invention achieves its objectives in that, in addition to a bearing for the shaft to which the rotor of the motor is connected, there is a further bearing through which the stator supporting part and the rotor are connected to one another.
Such a configuration makes it possible to ensure that the motor can be completely assembled and tested in the manufacturer""s factory, which is best equipped for such a purpose, before it is delivered to a user. With the solution according to the invention, there is no longer any need to unscrew locking pins and locking bolts and to remove spacers from between the stator supporting part and the rotor bell. Correspondingly, there is no need to return the locking pins and bolts together with the spacers to the motor factory.
To simplify assembly of a motor that has been preassembled according to the invention, in accordance with another feature of the invention, the rotor is in the form of a bell whose central part is a flat disk and, on a circle with the same radius, has access holes in the same way that the stator supporting part has mounting holes and, in the same way as the supporting star, has threaded holes for mounting the motor on the supporting star.
One particular advantage of the invention is, in accordance with a further feature of the invention, the stator supporting part and the rotor can be removed jointly from the supporting star and/or the washing machine.
In accordance with an added feature of the invention, the supporting star has a mounting flange with threaded holes accommodating the mounting bolts.
In accordance with an additional feature of the invention, the supporting star has mounting eyes with threaded holes accommodating the mounting bolts.
Apart from such a configuration, in accordance with yet another feature of the invention, the drive apparatus advantageously has the best protection in that the stator supporting part extends beyond the field windings and its rim, and, together with that of the bell, forms a labyrinth seal.
In accordance with yet a further feature of the invention, the stator supporting part and the bell each have a circumferential collar on the side facing the intermediate space. The two collars are separated from one another by a bearing, by which the rotor is held on the stator supporting part.
In accordance with yet an added feature of the invention, the rotor is a rotor bell, the stator support has a circumferential stator collar, the rotor bell has a circumferential rotor collar, and the further bearing is disposed between the stator collar and the rotor collar.
In accordance with yet an additional feature of the invention, the stator support and the rotor bell are separated by an intermediate space, the circumferential stator collar is disposed on the stator support on a side facing the intermediate space, and the circumferential rotor collar is disposed on the rotor bell on a side facing the intermediate space.
In accordance with a concomitant feature of the invention, the stator supporting part has a central guide sleeve that can be placed, with a defined sliding fit, onto an outer cylinder of the bearing sleeve of the supporting star. The configuration makes it easier to install the motor on the washing machine because the motor, still locked, can be placed with its guide sleeve securely mounted onto the bearing sleeve so that the central hole for mounting the rotor bell on the shaft journal is automatically centered.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a drive apparatus for a washing machine, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.